<script>
import { isActive, hashRE, groupHeaders } from '../util'

export default {
  functional: true,

  props: ['item', 'sidebarDepth'],

  render(
    h,
    {
      parent: { $page, $site, $route, $themeConfig, $themeLocaleConfig },
      props: { item, sidebarDepth },
    }
  ) {
    // use custom active class matching logic
    // due to edge case of paths ending with / + hash
    const selfActive = isActive($route, item.path)
    // for sidebar: auto pages, a hash link should be active if one of its child
    // matches
    const active =
      item.type === 'auto'
        ? selfActive ||
          item.children.some(c =>
            isActive($route, item.basePath + '#' + c.slug)
          )
        : selfActive
    const link =
      item.type === 'external'
        ? renderExternal(h, item.path, item.title || item.path)
        : renderLink(h, item.path, item.title || item.path, active)

    const maxDepth = [
      $page.frontmatter.sidebarDepth,
      sidebarDepth,
      $themeLocaleConfig.sidebarDepth,
      $themeConfig.sidebarDepth,
      1,
    ].find(depth => depth !== undefined)

    const displayAllHeaders =
      $themeLocaleConfig.displayAllHeaders || $themeConfig.displayAllHeaders

    if (item.type === 'auto') {
      return [
        link,
        renderChildren(h, item.children, item.basePath, $route, maxDepth),
      ]
    } else if (
      (active || displayAllHeaders) &&
      item.headers &&
      !hashRE.test(item.path)
    ) {
      const children = groupHeaders(item.headers)
      return [link, renderChildren(h, children, item.path, $route, maxDepth)]
    } else {
      return link
    }
  },
}

function renderLink(h, to, text, active) {
  return h(
    'router-link',
    {
      props: {
        to,
        activeClass: '',
        exactActiveClass: '',
      },
      class: {
        active,
        'sidebar-link': true,
      },
    },
    text
  )
}

function renderChildren(h, children, path, route, maxDepth, depth = 1) {
  if (!children || depth > maxDepth) return null
  return h(
    'ul',
    { class: 'sidebar-sub-headers' },
    children.map(c => {
      const active = isActive(route, path + '#' + c.slug)
      return h('li', { class: 'sidebar-sub-header' }, [
        renderLink(h, path + '#' + c.slug, c.title, active),
        renderChildren(h, c.children, path, route, maxDepth, depth + 1),
      ])
    })
  )
}

function renderExternal(h, to, text) {
  return h(
    'a',
    {
      attrs: {
        href: to,
        target: '_blank',
        rel: 'noopener noreferrer',
      },
      class: {
        'sidebar-link': true,
      },
    },
    [text, h('OutboundLink')]
  )
}
</script>

<style lang="stylus">
.sidebar .sidebar-sub-headers {
  padding-left: 1rem;
  font-size: 0.95em;
}

a.sidebar-link {
  font-size: 1em;
  font-weight: 400;
  display: inline-block;
  color: var(--textColor);
  border-left: 0.25rem solid transparent;
  padding: 0.35rem 1rem 0.35rem 1.25rem;
  line-height: 1.4;
  width: 100%;
  box-sizing: border-box;

  &:hover {
    color: $accentColor;
  }

  &.active {
    font-weight: 600;
    color: $accentColor;
    border-left-color: $accentColor;
  }

  .sidebar-group & {
    padding-left: 2rem;
  }

  .sidebar-sub-headers & {
    padding-top: 0.25rem;
    padding-bottom: 0.25rem;
    border-left: none;

    &.active {
      font-weight: 500;
    }
  }
}
</style>
